Method of forming p-type doped silicon-germanium layers and system for forming same

Abstract

Methods and systems for forming a p-type doped silicon germanium layer. The p-type doped silicon germanium layer can include silicon, germanium, gallium, and, in at least some cases, indium.

What is claimed is: 
     
         1 . A method of forming a p-type doped silicon germanium layer, the method comprising the steps of:
 providing a substrate within a reaction chamber of a reactor; and   forming the p-type doped silicon germanium layer, the step of forming comprising:
 providing a silicon precursor to the reaction chamber; 
 providing a germanium precursor to the reaction chamber; and 
 providing one or more p-type dopant precursors to the reaction chamber, 
   
       wherein the one or more p-type dopant precursors comprise boron, gallium and indium. 
     
     
         2 . The method according to  claim 1 , wherein the p-type doped silicon germanium layer is epitaxially formed on the substrate. 
     
     
         3 . The method according to  claim 1 , wherein a temperature during the step of forming the p-type doped silicon germanium layer is less than 800° C. or between about 300° C. and about 800° C. or between about 350° C. and about 500° C. 
     
     
         4 . The method according to  claim 1 , wherein the one or more p-type dopant precursors comprise one or more of a borane having a formula B x H y  where x is between 1-12 and where y≥x and y≤3x, deuterium-diborane (B 2 D 6 ), or one or more borohydride compounds. 
     
     
         5 . The method according to  claim 4 , wherein the one or more borohydride compounds comprise a borohydride represented by the formula Y x M(BH 4 ) 3−x , wherein Y is independently chosen from hydrogen, deuterium, chlorine, bromine, and iodine; M is a Group 13 metal independently chosen from gallium and indium; and x is an integer from 0-2. 
     
     
         6 . The method according to  claim 4 , wherein the one or more borohydride compounds are selected from the group consisting of gallium borohydride (Ga(BH 4 ) 3 ) and indium borohydride (In(BH 4 ) 3 ). 
     
     
         7 . The method according to  claim 4 , wherein the one or more borohydride compounds comprise a borohydride represented by the formula R x M(BH 4 ) 3−x , wherein R is independently chosen from CH 3 , C 2 H 5 , C 6 H 5 , CF 3 SO 3 , and NH 2 ; M is a Group 13 metal independently chosen from gallium and indium; and x is an integer from 1 to 3. 
     
     
         8 . The method according to  claim 1 , wherein the one or more p-type dopant precursors comprise one or more of an indium organometallic compound and an indium halide compound. 
     
     
         9 . The method according to  claim 1 , wherein the one or more p-type dopant precursors comprise one or more of an indium alkyl compound and an indium alkyl-amino compound. 
     
     
         10 . The method according to  claim 1 , wherein the one or more p-type dopant precursors comprise one or more of trimethylindium, triethylindium, dimethylaminopropyl-dimethyl-indium, indium trichloride, and indium compounds comprising one or more adducts selected from the group BH 3 —NR 3 , BH 3 —SR 2 , and B(NR 2 ) 3 , wherein each R can be independently selected from hydrogen, methyl, ethyl, 1-propyl, 2-propyl, cyclopropyl, 1-butyl, 2-butyl, 2-methylpropyl, tert-butyl, cyclobutyl, 1-pentyl, 1,1-dimethylpropyl, 2,2-dimethylpropyl, 3-methylbutyl, 1-methylbutyl, 1-ethylpropyl, 1,2-dimethylpropyl, 2-methylbutyl, cyclopentyl, 1-hexyl, 2-hexyl, 3-hexyl, 1-methyl-1-ethylpropyl, 1,1-dimethylbutyl, cyclohexyl, phenyl, benzyl, trimethylsilyl, and triethylsilyl functional groups. 
     
     
         11 . The method according to  claim 1 , wherein a concentration of indium in the p-type doped silicon germanium layer is greater than 0 at % and not more than 2 at % or greater than 0.1 at % and not more than 1.5 at %. 
     
     
         12 . A method of forming a p-type doped silicon germanium layer, the method comprising the steps of:
 providing a substrate within a reaction chamber of a reactor; and   forming the p-type doped silicon germanium layer comprising boron and gallium, the step of forming comprising:
 providing a silicon precursor to the reaction chamber; 
 providing a germanium precursor to the reaction chamber; and 
 providing one or more p-type dopant precursors to the reaction chamber, 
   
       wherein the one or more p-type dopant precursors comprise one or more of gallium tribromide or gallium triiodide. 
     
     
         13 . The method according to  claim 12 , wherein the silicon precursor comprises one or more of a silane, an alkylsilane, a halogen-substituted silane, or a silicon precursor including two or more silicon atoms. 
     
     
         14 . The method according to  claim 12 , wherein one or more p-type dopant precursors further comprises a boron precursor. 
     
     
         15 . The method according to  claim 14 , wherein the boron precursor comprises one or more of a borane, deuterium-diborane (B 2 D 6 ), or one or more borohydrides. 
     
     
         16 . The method of  claim 12 , wherein the one or more p-type dopant precursors further comprises an indium precursor. 
     
     
         17 . The method of  claim 12 , wherein a temperature of the substrate is less than 450° C., less than 400° C., or between about 300° C. and about 400° C. or between about 320° C. and about 380° C. 
     
     
         18 . A method of forming a p-type doped silicon germanium layer, the method comprising the steps of:
 providing a substrate within a reaction chamber of a reactor; and   forming the p-type doped silicon germanium layer, the step of forming comprising:
 providing a silicon precursor to the reaction chamber; 
 providing a germanium precursor to the reaction chamber; and 
 providing one or more p-type dopant precursors to the reaction chamber, 
 wherein the silicon precursor comprises one or more of bromine and iodine. 
   
     
     
         19 . The method according to  claim 18 , wherein the silicon precursor is represented by the formula SiX a H 4−a , wherein each X is an independently selected halogen selected from the group consisting of I and Br; and a is at least 1 and not more than  4  or the formula Si a X2 a+2−n H n , where a is from 2 to 5 or the formula Si a X2 a−n H n , where a is 3-6. 
     
     
         20 . The method according to  claim 18 , wherein the p-type doped silicon germanium layer comprises boron and gallium. 
     
     
         21 . The method of  claim 12 , wherein a temperature of the substrate is less than 450° C., less than 400° C., or between about 300° C. and about 400° C. or between about 320° C. and about 380° C. 
     
     
         22 . The method of  claim 12 , wherein the p-type doped silicon germanium layer is selectively formed overlying a first surface of the substrate, relative to a second surface of the substrate. 
     
     
         23 . The method of  claim 22 , wherein an etchant is not used during the step of forming the p-type doped silicon germanium layer. 
     
     
         24 . A method of forming one or more of a source region and a drain region of a device using the method of  claim 1 . 
     
     
         25 . A structure comprising:
 one or more of a source and a drain region formed according to the method of  claim 1 .